Tetramethylpiperidine compounds for use as stabilizers for organic materials

ABSTRACT

Novel piperidine compounds of the formula (I)   &lt;IMAGE&gt; (I)  in which R1 is e.g. hydrogen or methyl, n is e.g. 1 and A is e.g. -COR2 with R2 being C1-C18alkyl. The said compounds are effective as light stabilisers, heat stabilizers and oxidation stabilisers for organic materials.

This is a continuation of application Ser. No. 07/910,600, filed on Jul.8, 1992, now abandoned.

The present invention relates to novel piperidine compounds, to the usethereof as light stabilisers, heat stabilisers and oxidation stabilisersfor organic materials, in particular synthetic polymers, and to theorganic materials thus stabilised.

The stabilisation of synthetic polymers by derivatives of2,2,6,6-tetramethylpiperidine has been described in numerouspublications, in particular in U.S. Pat. Nos. 3,684,765, 3,904,581,4,108,829, 4,316,025, 4,433,145, 4,533,688 and 4,740,544, European LaidOpen Prints 117,229, 176,106 and 410,934.

The present invention relates to novel compounds of the formula (I)##STR2##

in which R₁ is hydrogen, C₁ -C₈ alkyl, O, OH, NO, CH₂ CN, C₁ -C₁₈alkoxy, C₅ -C₁₂ cycloalkoxy, C₃ -C₆ alkenyl, C₇ -C₉ phenylalkyl which isunsubstituted or mono-, di- or tri-substituted on the phenyl by C₁ -C₄alkyl; or R₁ is C₁ -C₈ acyl;

n is 1, 2, 3 or 4;

when n is 1, A is C₁ -C₁₈ alkyl, C₃ -C₆ alkenyl, C₇ -C₉ phenylalkylwhich is unsubstituted or mono-, di- or tri-substituted on the phenyl byC₁ -C₄ alyl; or A is also one of the groups of the formulae (IIa)-(IIc)##STR3## in which X₁ and X₂ which can be identified or different are agroup --OR₄, --SR₄ or ##STR4## where R₄, R₅ and R₆ which can beidentical or different are hydrogen, C₁ -C₁₈ alkyl, C₅ -C₁₂ cycloalkylwhich is unsubstituted or mono-, di- or tri-substituted by C₁ -C₄ alkyl;C₃ -C₁₈ alkenyl, phenyl which is unsubstituted or mono-, di- ortri-substituted by C₁ -C₄ alkyl or C₁ -C₄ alkoxy; C₇ -C₉ phenylalkylwhich is unsubstituted or mono-, di- or tri-substituted on the phenyl byC₁ -C₄ alkyl; C₂ -C₄ alkyl substituted in the 2-, 3- or 4-position byOH, by C₁ -C₈ alkoxy, by di(C₁ -C₄ alkyl)amino or by 1-pyrrolidyl,1-piperidyl, 4-morpholinyl, 4-methyl-1-piperazinyl or1-hexahydroazepinyl; tetrahydrofurfuryl or a group of the formula (III)##STR5## where R₇ is as defined for R₁ ; or ##STR6## is 1-pyrrolidyl,1-piperidyl, 4-morpholinyl, 4-methyl-l-piperazinyl or1-hexahydroazepinyl; or X₁ and X₂ are one of the groups of the formulae(IVa)-(IVc) ##STR7## with R₇ being as defined above;

R₂ is hydrogen, C₁ -C₁₈ alkyl, C₅ -C₁₂ cycloalkyl which is unsubstitutedor mono-, di- or tri-substituted by C₁ -C₄ alkyl; C₂ -C₁₈ alkenyl,phenyl which is unsubstituted or mono-, di- or tri-substituted by C₁ -C₄alkyl or C₁ -C₄ alkoxy and/or monosubstituted by an OH group; C₇ -C₉phenylalkyl which is unsubstituted or mono-, di- or tri-substituted onthe phenyl by C₁ -C₄ alkyl and/or monosubstituted by an OH group;

p is zero or 1;

R₃ is C₁ -C₁₈ alkyl, C₅ -C₁₂ cycloalkyl which is unsubstituted or mono-,di- or tri-substituted by C₁ -C₄ alkyl; C₃ -C₁₈ alkenyl, C₇ -C₉phenylalkyl which is unsubstituted or mono-, di- or tri-substituted onthe phenyl by C₁ -C₄ alkyl; or a group of the formula (III);

when n is 2, A is C₂ -C₁₂ alkylene, C₄ -C₁₂ alkylene interrupted by 1, 2or 3 oxygen atoms; 2-hydroxytrimethylene, phenylenedimethylene or one ofthe groups of the formulae (Va)-(Ve) ##STR8## in which X₃ is as definedabove for X₁ and X₂ ; or X₃ is a group of the formula (VI) ##STR9## withR 1 being as defined above;

E₁ is one of the groups of the formulae (VIIa)-(VIIc) ##STR10## in whichG₁, G₂ and G₃ which can be identical or different are --O-- or ##STR11##where R₁₄ is hydrogen, C₁ -C₁₈ alkyl, C₅ -C₁₂ cycloalkyl which isunsubstituted or mono-, di- or tri-substituted by C₁ -C₄ alkyl; C₇ -C₉phenylalkyl which is unsubstituted or mono-, di- or tri-substituted onthe phenyl by C₁ -C₄ alkyl; or a group of the formula (III);

R₁₀ is C₂ -C₁₂ alkylene, C₄ -C₁₂ alkylene interrupted by 1, 2 or 3oxygen atoms or by 1 or 2 ##STR12## groups where R is as defined abovefor R₁₄ or is C₁ -C₈ acyl or (C₁ -C₈ alkoxy)carbonyl; C₅ -C₇cycloalkylene, C₅ -C₇ cycloalkylenedi(C₁ -C₄ alkylene), C₁ -C₄alkylenedi(C₅ -C₇ cycloalkylene), C₂ -C₄ alkylidenedi(C₅ -C₇cycloalkylene), phenylene, phenylenedi(C₁ -C₄ alkylene), C₁ -C₄alkylenediphenylene or C₂ -C₄ alkylidenediphenylene;

R₁₁ is C₂ -C₆ alkylene;

G₄ is one of the groups>N--(R₁₁ -G₃)_(s) --,>CH--O-- or ##STR13## withR₁₄ being as defined above;

r and s which can be identical or different are zero or 1;

R₁₂ is hydrogen or, when r is 1 and G₄ is >CH--O--, R₁₂ is also methyl;

R₁₃ is hydrogen or methyl;

R₈ is a direct bond, C₁ -C₁₂ alkylene, C₂ -C₄ alkenylene, cyclohexylene,cyclohexenylene or phenylene;

R₉ is C₂ -C₁₂ alkylene, C₄ -C₁₂ alkylene interrupted by 1, 2 or 3 oxygenatoms;

C₅ -C₇ cycloalkylene, C₅ -C₇ cycloalkylenedi(C₁ -C₄ alkylene) or

C₂ -C₄ alkylidenedi(C₅ -C₇ cycloalkylene);

q is zero or an integer from 1 to 10;

when n is 3, A is aliphatic C₄ -C₁₈ triacyl, aromatic C₉ -C₁₈ triacyl ora group of the formula (VIII) ##STR14## in which X₃ is as defined above;

E₂ is one of the groups of the formulae (IXa)-(IXc) ##STR15## in whichG₅, G₆ and G₇ which can be identical or different are as defined abovefor G₁, G₂ and G₃ ;

R₁₆, R₁₇ and R₁₈ which can be identical or different are C₂ -C₆alkylene;

t is zero or 1;

R₁₉, R₂₀ and R₂₁ which can be identical or different are as definedabove for R₁₄ ;

G₈ is a direct bond or --CH₂ --;

u and v which can be identical or different are integers from 2 to 6;and

R₂₂ is C₃ -C₁₂ alkanetriyl;

when n is 4, A is aliphatic C₆ -C₁₈ tetraacyl, aromatic C10-C18tetraacylor a group of the formula (Xa) or (Xb) ##STR16## in which X₃ is asdefined above;

E₃ is a group of the formulae (XIa)-(XIc) ##STR17## in which G₉ is asdefined above for G₁, G₂ and G₃ ;

R₂₃ and R₂₄ which can be identical or different are C₂ -C₆ alkylene;

w is zero or 1; and

R₂₅ is C₄ -C₁₂ alkanetetrayl.

Examples of alkyl having not more than 18 carbon atoms are methyl,ethyl, propyl, isopropyl, butyl, 2-butyl, isobutyl, t-butyl, pentyl,2-pentyl, hexyl, heptyl, octyl, 2-ethylhexyl, t-octyl, nonyl, decyl,undecyl, dodecyl, tridecyl, tetradecyl, hexadecyl and octadecyl.

Examples of OH-substituted C₂ -C₄ alkyl are 2-hydroxyethyl,2-hydroxypropyl, 3-hydroxypropyl, 2-hydroxybutyl and 4-hydroxybutyl.2-Hydroxyethyl is preferred.

Examples of C₂ -C₄ alkyl substituted by C₁ -C₈ alkoxy, preferably C₁ -C₄alkoxy, in particular methoxy or ethoxy, are 2-methoxyethyl,2-ethoxyethyl, 3-methoxypropyl, 3-ethoxypropyl, 3-butoxypropyl,3-octoxypropyl and 4-methoxybutyl.

Examples of C₂ -C₄ alkyl substituted by di(C₁ -C₄ alkyl)amino,preferably by dimethylamino or diethylamino, are 2-dimethylaminoethyl,2-diethylaminoethyl, 3-dimethylaminopropyl, 3-diethylaminopropyl,3-dibutylaminopropyl and 4-diethylaminobutyl.

Examples of C₂ -C₄ alkyl substituted by a 5- to 7-memberednitrogen-containing heterocyclic group are the groups of the formula##STR18## in which X is a direct bond, --O--, ##STR19## --CH₂ -- or--CH₂ CH₂ --. ##STR20## is preferred.

Examples of alkoxy having not more than 18 carbon atoms are methoxy,ethoxy, propoxy, isopropoxy, butoxy, isobutoxy, pentoxy, isopentoxy,hexoxy, heptoxy, octoxy, decyloxy, dodecyloxy, tetradecyloxy,hexadecyloxy and octadecyloxy. C₆ -C₁₂ alkoxy, in particular heptoxy oroctoxy, are preferred for R₁ and R₇.

Examples of unsubstituted or substituted C₅ -C₁₂ cycloalkyl arecyclopentyl, methylcyclopentyl, dimethylcyclopentyl, cyclohexyl,methylcyclohexyl, dimethylcyclohexyl, trimethylcyclohexyl,t-butylcyclohexyl, cyclooctyl, cyclodecyl and cyclododecyl; cyclohexylwhich is unsubstituted or substituted by C₁ -C₄ alkyl is preferred.

Representative examples of C₅ -C₁₂ cycloalkoxy R₁ and R₇ arecyclopentoxy, cyclohexoxy, cycloheptoxy, cyclooctoxy, cyclodecyloxy andcyclododecyloxy. Cyclopentoxy and cyclohexoxy are preferred.

Examples of alkenyl having not more than 18 carbon atoms are vinyl,allyl, 2-methylallyl, butenyl, hexenyl, decenyl, undecenyl and oleyl.

Examples of substituted phenyl are methylphenyl, dimethylphenyl,trimethylphenyl, t-butylphenyl, di-t-butylphenyl,3,5-di-t-butyl-4-methylphenyl, methoxyphenyl, ethoxyphenyl,hydroxyphenyl and 3,5-di-t-butyl-4-hydroxyphenyl.

Examples of phenylalkyl which is unsubstituted or substituted on thephenyl are benzyl, methylbenzyl, dimethylbenzyl, trimethylbenzyl,t-butylbenzyl, 2-phenylethyl and 2-(3,5-di-t-butyl-4-hydroxyphenyl)-ethyl.

Acyl having not more than 8 carbon atoms can be an aliphatic or aromaticgroup. Representative examples are formyl, acetyl, propionyl, butyryl,pentanoyl, hexanoyl, heptanoyl, octanoyl, benzoyl, acryloyl or crotonyl.C₁ -C₈ alkanoyl, C₃ -C₈ alkenoyl and benzoyl are preferred. Acetyl isespecially preferred. The carbon atom in the 1-position is convenientlysaturated in the acyl radical.

Representative examples of a 5- to 7-membered heterocyclic group##STR21## are 1-pyrrolidyl, 1-piperidyl, 4-morpholinyl,4-methyl-1-piperazinyl and 1-hexahydroazepinyl. 4-Morpholinyl ispreferred.

Examples of alkylene having not more than 12 carbon atoms are methylene,ethylene, propylene, trimethylene, tetramethylene, pentamethylene,2,2-dimethyltrimethylene, hexamethylene, trimethylhexamethylene,decamethylene and dodecamethylene.

Examples of C₄ -C₁₂ alkylene interrupted by 1, 2 or 3 oxygen atoms are3-oxapentane-1,5-diyl, 3,6-dioxaoctane-1,8-diyl,4,7-dioxadecane-1,10-diyl, 4,9-dioxadodecane-1,12-diyl,3,6,9-trioxaundecane-1,11-diyl and 4,7,10-trioxatridecane-1,13-diyl.

Preferred examples of C₄ -C₁₂ alkylene R₁₀ interrupted by 1 or 2##STR22## groups are the groups ##STR23## .

Representative examples of groups containing 1 or 2 C₅ -C₇ cycloalkylenegroups are cyclohexylene, methylcyclohexylene, cyclohexylenedimethylene,methylenedicyclohexylene and isopropylidenedicyclohexylene.

Representative examples of groups containing 1 or 2 phenylene groups arephenylene, methylphenylene, dimethylphenylene, phenylenedimethylene,methylenediphenylene and isopropylidenediphenylene.

Examples of C₂ -C₄ alkenylene are vinylene, methylvinylene anddimethylvinylene.

Aliphatic C₄ -C₁₈ triacryl A can be unsubstituted or substituted by anOH group. Preferred examples are the triacyls derived frommethanetricarboxylic, 1,1,2-ethanetricarboxylic,1,2,3-propanetricarboxylic, citric or 1,2,3-butanetricarboxylic acids.

Aromatic C₉ -C₁₈ triacyl A is, for example, a triacyl derived from1,2,4-benzenetricarboxylic or 1,3,5-benzenetricarboxylic acid.

Preferred examples of C₃ -C₁₂ alkanetriyl R₂₂ are 1,2,3-propanetriyl,1,2,4-butanetriyl, 1,2,6-hexanetriyl or a group ##STR24## .

Aliphatic C₆ -C₁₈ stetraacyl A is, for example, a tetraacyl derived from1,1,3,3-propanetetracarboxylic acid or from1,2,3,4-butanetetracarboxylic acid.

Aromatic C₁₀ -C₁₈ tetraacyl A is, for example, a tetraacyl derived from1,2,4,5-benzenetetracarboxylic acid.

Preferred examples of C₄ -C₁₂ alkanetetrayl R₂₅ are1,2,3,4-butanetetrayl and the group ##STR25##

(C₁ -C₈ alkoxy)carbonyl is for example methoxycarbonyl, ethoxycarbonyl,propoxycarbonyl, butoxycarbonyl, pentoxycarbonyl, hexoxycarbonyl,heptoxycarbonyl and octoxycarbonyl.

The preferred definitions of R₁ and R₇ are hydrogen, C₁ -C₄ alkyl, OH,C₆ -C₁₂ alkoxy, C₅ -C₈ cycloalkoxy, allyl, benzyl or acetyl, inparticular hydrogen or methyl.

Those compounds of the formula (I) are preferred in which n is 1, 2, 3or 4 and, when n is 1, A is C₁ -C₁₈ alkyl, C₃ -C₄ alkenyl, benzyl whichis unsubstituted or mono-, di- or tri-substituted on the phenyl by C₁-C₄ alkyl; or A is one of the groups of the formulae (IIa)-(IIc) inwhich X₁ and X₂ which can be identical or different are a group --OR₄,--SR₄ or ##STR26## where R₄, R₅ and R₆ which can be identical ordifferent are hydrogen, C₁ -C₁₈ alkyl, C₅ -C₈ cycloalkyl which isunsubstituted or mono-, di- or tri-substituted by C₁ -C₄ alkyl; C₃ -C₁₈alkenyl, phenyl which is unsubstituted or mono-, di- or tri-substitutedby C₁ -C₄ alkyl or C₁ -C₄ alkoxy; benzyl which is unsubstituted ormono-, di- or tri-substituted on the phenyl by C₁ -C₄ alkyl; C₂ -C₃alkyl substituted in the 2- or 3-position by OH, by C₁ -C₄ alkoxy, bydi(C₁ -C₄ alkyl)amino or by a group ##STR27## where X is a direct bond,--O--, --CH₂ -- or --CH₂ CH₂ --; tetrahydrofurfuryl or a group of theformula (III), or the group ##STR28## is a group ##STR29## as definedabove, or X₁ and X₂ are one of the groups of the formulae (IVa)-(IVc),R₂ is hydrogen, C₁ -C₁₇ alkyl, C₅ -C₈ cycloalkyl which is unsubstitutedor mono-, di- or tri-substituted by C₁ -C₄ alkyl; C₂ -C₁₇ alkenyl,phenyl which is unsubstituted or mono-, di- or tri-substituted by C₁ -C₄alkyl or C₁ -C₄ alkoxy and/or monosubstituted by an OH group; benzyl orphenylethyl which, both, are unsubstituted or mono-, di- ortri-substituted on the phenyl by C₁ -C₄ alkyl and/or monosubstituted byan OH group; p is zero or 1, R₃ is C₁ -C₁₈ alkyl, C₅ -C₈ cycloalkylwhich is unsubstituted or mono-, di- or tri-substituted by C₁ -C₄ alkyl;C₃ -C₁₈ alkenyl, benzyl which is unsubstituted or mono-, di- ortri-substituted on the phenyl by C₁ -C₄ alkyl; or a group of the formula(III), and, when n is 2, A is C₂ - C₁₀ alkylene, C₄ -C₁₀ alkyleneinterrupted by 1, 2 or 3 oxygen atoms; 2-hydroxytrimethylene,phenylenedimethylene or one of the groups of the formulae (Va)-(Ve) inwhich X₃ is as defined above for X₁ and X₂ or is a group of the formula(VI), E₁ is one of the groups of the formulae (VIIa)-(VIIc) in which G₁,G₂ and G₃ which can be identical or different are --O-- or ##STR30##where R₁₄ is hydrogen, C₁ -C₁₈ alkyl, C₅ -C₈ cycloalkyl which isunsubstituted or mono-, di- or tri-substituted by C₁ -C₄ alkyl; benzylwhich is unsubstituted or mono-, di- or tri-substituted on the phenyl byC₁ -C₄ alkyl; or a group of the formula (III), R₁₀ is C₂ -C₁₀ alkylene,C₄ -C₁₀ alkylene interrupted by 1, 2 or 3 oxygen atoms or by 1 or 2##STR31## groups where R₁₅ is as defined above for R₁₄ or is C₁ -C₆ acylor (C₁ -C₆ alkoxy)carbonyl; cyclohexylene, cyclohexylenedimethylene,methylenedicyclohexylene, isopropylidenedicyclohexylene, phenylene,phenylenedimethylene, methylenediphenylene, orisopropylidenediphenylene, R₁₁ is C₂ -C₄ alkylene, G₄ is >N--(R₁₁-G₃)_(s) --, ##STR32## with R₁₄ being as defined above, r and s which anbe identical or different are zero or 1; R₁₂ is hydrogen or, when r is 1and G₄ is >CH--O--, is also methyl; and R₁₃ is hydrogen or methyl, R₈ isa direct bond, C₁ -C₁₀ alkylene, vinylene, cyclohexylene or phenylene,R₉ is C₂ -C₁₀ alkylene, C₄ -C₁₀ alkylene interrupted by 1, 2 or 3 oxygenatoms; cyclohexylene, cyclohexylenedimethylene orisopropylidenedicyclohexylene and q is zero or an integer from 1 to 5,and, when n is 3, A is aliphatic C₄ -C₁₂ triacyl, aromatic C₉ -C₁₂triacyl or a group of the formula (VIII) in which X₃ is as defined aboveand E₂ is one of the groups of the formulae (IXa)-(IXc) in which G₅, G₆and G₇ which can be identical or different are as defined above for G₁,G₂ and G₃ ; R₁₆, R₁₇ and R₁₈ which can be identical or different are C₂-C₆ alkylene, t is zero or 1, R₁₉, R₂₀ and R₂₁ which can be identical ordifferent are as defined above for R₁₄ ; G₈ is a direct bond or --CH₂--, u and v which can be identical or different are integers from 2 to 6and R₂₂ is C₃ -C₁₀ alkanetriyl, and, when n is 4, A is aliphatic C₆ -C₁₂tetraacyl, aromatic C₁₀ -C₁₂ tetraacyl or a group of the formula (Xa) or(Xb) in which X₃ is as defined above and E₃ is a group of the formula(XIa)-(XIc) in which G₉ is as defined above for G₁, G₂ and G.sub. 3 ;R₂₃ and R₂₄ which can be identical or different are C₂ -C₆ alkylene, wis zero or 1 and R₂₅ is C₄ -C₈ alkanetetrayl.

Those compounds of the formula (I) are particularly preferred in which nis 1, 2, 3 or 4 and, when n is 1, A is methyl, C₄ -C₁₈ alkyl, allyl,benzyl or one of the groups of the formulae (IIa)-(IIc) in which X₁ andX₂ which can be identical or different are a group --OR₄, --SR₄ or##STR33## where R₄, R₅ and R₆ which can be identical or different arehydrogen, C₁ -C₁₂ alkyl, cyclohexyl which is unsubstituted or mono-, di-or tri-substituted by C₁ -C₄ alkyl; allyl, undecenyl, phenyl, benzyl, C₂-C₃ alkyl substituted in the 2- or 3-position by OH, by C₁ -C₄ alkoxy,by dimethylarnino, by diethylamino or by 4-morpholinyl;tetrahydrofurfuryl or a group of the formula (III), or the group##STR34## is 4-morpholinyl, or X₁ and X₂ are one of the groups of theformulae (IVa)-(IVc), R₂ is C₂ -C₁₇ alkyl, cyclohexyl which isunsubstituted or mono-, di- or tri-substituted by C₁ -C₄ alkyl; C₂ -C₁₀alkenyl, phenyl, t-butylphenyl, 3,5-di-t-butyl-4-hydroxyphenyl, benzylor 2-(3,5-di-t-butyl-4-hydroxyphenyl)-ethyl, p is zero or 1, R₃ is C₂-C₁₈ alkyl, cyclohexyl which is unsubstituted or mono-, di- ortri-substituted by C₁ -C₄ alkyl; allyl, undecenyl, oleyl, benzyl or agroup of the formula (III), and, when n is 2, A is C₂ -C₈ alkylene, C₄-C₈ alkylene interrupted by 1 or 2 oxygen atoms; 2-hydroxytrimethylene,phenylenedimethylene or one of the groups of the formulae (Va)-(Ve) inwhich X₃ is as defined above for X₁ and X₂ or is a group of the formula(VI), E₁ is one of the groups of the formulae (VIIa)-(VIIc) in which G₁,G₂ and G₃ which can be identical or different are --O-- or ##STR35##where R₁₄ is hydrogen, C₁ -C₁₂ alkyl, cyclohexyl which is unsubstitutedor mono-, di- or tri-substituted by C₁ -C₄ alkyl; benzyl or a group ofthe formula (III), R₁₀ is C₂ -C₈ alkylene, C₄ -C₁₀ alkylene interruptedby 1, 2 or 3 oxygen atoms or by 1 or 2 ##STR36## groups where R₁₅ is asdefined above for R₁₄ or is C₁ -C₄ acyl or (C₁ -C₄ alkoxy)carbonyl;cyclohexylenedimethylene, methylenedicyclohexylene,isopropylidenedicyclohexylene, phenylenedimethylene orisopropylidenediphenylene, R₁₁ is C₂ -C₃ alkylene, G₄ is >N--(R₁₁-G₃)_(s) -- or >CH--O--, r and s which can be identical or different arezero or 1; R₁₂ is hydrogen or, when r is 1 and G₄ is >CH--O--, is alsomethyl; and R₁₃ is hydrogen or methyl, R₈ is a direct bond or C₁ -C₈alkylene, R₉ is C₂ -C₈ alkylene, C₄ -C₈ alkylene interrupted by 1 or 2oxygen atoms; cyclohexylenedimethylene or isopropylidenedicyclohexyleneand q is zero or an integer from 1 to 3 and, when n is 3, A is aliphaticC₄ -C₈ triacyl, benzenetricarbonyl or a group of the formula (VIII) inwhich X₃ is as defined above and E₂ is one of the groups of the formulae(IXa)-(IXc) in which G₅, G₆ and G₇ which can be identical or differentare as defined above for G₁, G₂ and G₃ ; R₁₆, R₁₇ and R₁₈ which can beidentical or different are C₂ -C₄ alkylene, t is zero or 1, R₁₉, R₂₀ andR₂₁ which can be identical or different are as defined above for R₁₄ ;G₈ is a direct bond or --CH₂ --, u and v which can be identical ordifferent are integers from 3 to 6 and R₂₂ is C₃ -C₆ alkanetriyl, and,when n is 4, A is aliphatic C₆ -C₈ tetraacyl, benzenetetracarbonyl or agroup of the formula (Xa) or (Xb) in which X₃ is as defined above and E₃is a group of the formulae (XIa)-(XIc) in which G₉ is as defined abovefor G₁, G₂ and G₃ ; R.sub. 23 and R₂₄ which can be identical ordifferent are C₂ -C₄ alkylene, w is zero or 1 and R₂₅ is C₄ -C₆alkanetetrayl.

Those compounds of the formula (I) are of special interest in which n is1, 2, 3 or 4 and, when n is 1, A is methyl, C₈ -C₁₈ alkyl or one of thegroups of the formulae (IIa)-(IIc) in which X₁ and X₂ which can beidentical or different are a group --OR₄ or ##STR37## where R₄ is C₁ -C₈alkyl or a group of the formula (lID, R₅ and R₆ which can be identicalor different are C₁ -C₈ alkyl, cyclohexyl, C₂ -C₃ alkyl substituted inthe 2- or 3-position by methoxy, by ethoxy, by dimethylamino, bydiethylamino or by 4-morpholinyl; tetrahydrofurfuryl or a group of theformula (III) or R₅ is also hydrogen or the group ##STR38##4-morpholinyl, R₂ is C₃ -C₁₇ alkyl, cyclohexyl, phenyl,3,5-di-t-butyl-4-hydroxyphenyl or2-(3,5-di-t-butyl-4-hydroxyphenyl)-ethyl, p is zero, R₃ is C₄ -C₁₈alkyl, cyclohexyl, t-butylcyclohexyl or a group of the formula (lID,and, when n is 2, A is one of the groups of the formulae (Va)-(Ve) inwhich X₃ is as defined above for X₁ and X₂ or is a group of the formula(VI), E₁ is one of the groups of the formulae (VIIa)-(VIIc) in which G₁and G₂ which can be identical or different are --O-- or ##STR39## whereR₁₄ is hydrogen, C₁ -C₈ alkyl, cyclohexyl or a group of the formula(III), R₁₀ is C₂ -C₆ alkylene, C₆ -C₁₀ alkylene interrupted by 2 or 3oxygen atoms; cyclohexylenedimethylene or methylenedicyclohexylene, thegroup (VIIb) is one of the groups ##STR40## where r and s which can beidentical or different are zero or 1, R₁₄ is as defined above, and R₁₃is hydrogen or methyl, R₈ is C₂ -C₈ alkylene, R₉ is C₄ -C₈ alkylene orisopropylidenedicyclohexylene and q is zero or 1, and, when n is 3, A isa group of the formula (VIII) in which X₃ is as defined above and E₂ isa group of the formula (IXa) or (IXb) in which G₅ and G₆ which can beidentical or different are as defined above for G₁ and G₂ ; R₁₆ and R₁₇which can be identical or different are C₂ -C₃ alkylene, t is zero, R₁₉,R₂₀ and R₂₁ are as defined above for R₁₄ ; G₈ is a direct bond or --CH₂-- and u and v which can be identical or different are integers from 3to 5, and, when n is 4, A is a group of the formula (Xa) in which X₃ isas defined above and E₃ is a group of the formula (XIa) in which G₉ isas defined above for G₁ and G₂ ; R₂₃ and R₂₄ which can be identical ordifferent are C₂ -C₃ alkylene and w is zero or 1.

Those compounds of the formula (I) are of particular interest in whichR₁ is hydrogen or methyl, n is 1, 2, 3 or 4 and, when n is 1, A ismethyl or one of the groups of the formulae (IIa)-(IIc) in which X₁ andX₂ which can be identical or different are a group --OR₄ or ##STR41##where R₄ is C₁ -C₄ alkyl, 2,2,6,6-tetramethyl-4-piperidyl or1,2,2,6,6-pentamethyl-4-piperidyl, R₅ and R₆ which can be identical ordifferent are C₁ -C₄ alkyl, cyclohexyl, tetrahydrofurfuryl,2,2,6,6-tetramethyl-4-piperidyl or 1,2,2,6,6opentamethyl-4-piperidyl orR₅ is also hydrogen or the group ##STR42## is 4-morpholinyl, R₂ is C₅-C₁₇ alkyl, p is zero and R₃ is C₆ -C₁₈ alkyl, and, when n is 2, A isone of the groups of the formulae (Va)-(Vd) in which X₃ is as definedabove for X₁ and X₂ or is a group of the formula (VI), E₁ is a group##STR43## where R₁₄ is hydrogen, methyl, 2,2,6,6-tetramethyl-4-piperidylor 1,2,2,6,6-pentamethyl-4-piperidyl, R₈ is C₄ -C₈ alkylene and R₉ is C₄-C₆ alkylene, and, when n is 3, A is a group of the formula (VIII) inwhich X₃ is as defined above and E₂ is a group ##STR44## where R₁₄ is asdefined above, and, when n is 4, A is a group of the formula (Xa) inwhich X₃ is as defined above and E₃ is a group ##STR45## with R₁₄ beingas defined above.

Those compounds of the formula (I) are also of interest in which R₁ ishydrogen or methyl, n is 1, 2, 3 or 4 and, when n is 1, A is methyl or agroup of the formula (IIb) in which R₂ is C₅ -C₁₇ alkyl, and, when n is2, A is a group of the formula (Va) or (Vb), in which X₃ is a group ofthe formula (VI) and E₁ is a group ##STR46## where R₁₄ is2,2,6,6-tetramethyl-4-piperidyl or 1,2,2,6,6-pentamethyl-4-piperidyl,and, when n is 3, A is a group of the formula (VIII) in which X₃ is asdefined above and E₂ is a group ##STR47## and, when n is 4, A is a groupof the formula (Xa) in which X₃ is as defined above and E₃ is a group##STR48##

The compounds of the formula (I) can be prepared by processes known perse, e.g. by reactingN,1-bis(2,2,6,6-tetramethyl-4-piperidyl)-4-piperidinemethanamine of theformula ##STR49## with suitable alkylating or acylating reagents in theappropriate molar ratios.

In this way, the compounds of the formula (I) with R₁ =H are obtained,from which the corresponding compounds with R₁ ≠H can subsequently beobtained.

The reactions are conveniently carried out in an inert solvent,operating at temperatures from e.g. -20° to 200° C., preferably from-10° to 180° C.

The N,1-bis(2,2,6,6-tetramethyl-4-piperidyl)-4-piperidinemethanamine canbe prepared, for example, according to scheme 1, by reacting 2 mol of2,2,6,6-tetramethyl-4-piperidone with 1 mol of 4-piperidinemethanaminein order to obtain an enamine-ketimine of the formula (XII) which isthen hydrogenated in the presence of a hydrogenation catalyst such asplatinum, palladium or nickel. ##STR50##

The reactions according to scheme 1 are preferably carried out in thesame reactor. The enamine-ketimine of the formula (XII) can be preparedwithout solvent or in the presence of a hydrocarbon solvent having aboiling point between e.g. 60° and 180° C., preferably between 80° and140° C., if appropriate in the presence of an organic acid or inorganicacid, for example benzoic or sulfuric acid; the hydrogenation ispreferably carried out in the presence of a C₁ -C₄ alkanol.

The reagents used are commercially available and can be prepared byknown processes.

As mentioned at the outset, the compounds of the formula (I) are highlyeffective in improving the light stability, heat stability and oxidationstability of organic materials, in particular synthetic polymers andcopolymers.

Examples of such organic materials which can be stabilised are:

1. Polymers of monoolefins and diolefins, for example polypropylene,polyisobutylene, polybutene-1, polymethylpentene-1, polyisoprene orpolybutadiene, as well as polymers of cycloolefins, for instance ofcyclopentene or norbornene, polyethylene (which optionally can becrosslinked), for example high density polyethylene (HDPE), low densitypolyethylene (LDPE), linear low density polyethylene (LLDPE), branchedlow density polyethylene (BLDPE).

2. Mixtures of the polymers mentioned under 1 ), for example mixtures ofpolypropylene with polyisobutylene, polypropylene with polyethylene (forexample PP/HDPE, PP/LDPE) and mixtures of different types ofpolyethylene (for example LDPE/HDPE).

3. Copolymers of monoolefines and diolefines with each other or withother vinyl monomers, such as, for example, ethylene/propylene, linearlow density polyethylene (LLDPE) and its mixtures with low densitypolyethylene (LDPE), propylene/butene-1, ethylene/hexene,ethylene/ethylpentene, ethylene/heptene, ethylene/octene,propylene/isobutylene, ethylene/butene-1, propylene/butadiene,isobutylene/isoprene, ethylene/alkyl acrylates, ethylene/alkylmethacrylates, ethylene/vinyl acetate copolymers and their copolymerswith carbon monoxide or ethylene/acrylic acid copolymers and their salts(ionomers) and terpolymers of ethylene with propylene and a diene, suchas hexadiene, dicyclopentadiene or ethylidene-norbornene; as well asmixtures of such copolymers and their mixtures with polymers mentionedin 1 ) above, for example polypropylene/ethylene-propylene-copolymers,LDPE/ethylene-vinyl acetate copolymers (EVA), LDPE/ethylene-acrylic acidcopolymers (EAA), LLDPE/EVA, LLDPE/EAA and statistical or alternatingpolyalkylene/carbon monoxide-copolymers as well as their mixtures withother polymers, for example polyamide.

3a. Hydrocarbon resins (for example C₅ -C₉) and hydrogenatedmodifications thereof (for example tackyfiers) and mixtures ofpolyalkylenes and starch.

4. Polystyrene, poly-(p-methylstyrcnc), poly-(α-methylstyrene).

5. Copolymers of styrene or α-methylstyrene with dienes or acrylicderivatives, such as, for example, styrene/butadiene,styrene/acrylonitrile, styrene/alkyl methacrylate, styrene/maleicanhydride, styrene/butadiene/alkyl acrylate, styrene/butadiene/alkylmethacrylate styrene/acrylonitrile/methyl acrylate; mixtures of highimpact strength from styrene copolymers and another polymer, such as,for example, from a polyacrylate, a diene polymer or anethylene/propylene/diene terpolymer; and block copolymers of styrene,such as, for example, styrene/butadiene/styrene,styrene/isoprene/styrene, styrene/ethylene/butylene/styrene orstyrene/ethylene/propylene/styrene.

6. Graft copolymers of styrene or α-methylstyrene such as, for example,styrene on polybutadiene, styrene on polybutadiene-styrene orpolybutadiene-acrylonitrile; styrene and acrylonitrile (ormethacrylonitrile) on polybutadiene; styrene and maleic anhydride ormaleimide on polybutadiene; styrene, acrylonitrile and maleic anhydrideor maleimide on polybutadiene; styrene, acrylonitrile and methylmethacrylate on polybumdiene, styrene and alkyl acrylates ormethacrylates on polybutadiene, styrene and acrylonitrile onethylene/propylene/diene terpolymers, styrene and acrylonitrile onpolyacrylates or polymethacrylates, styrene and acrylonitrile onacrylate/butadiene copolymers, as well as mixtures thereof with thecopolymers listed under 5), for instance the copolymer mixtures known asABS-, MBS-, ASA- or AES-polymers.

7. Halogen-containing polymers, such as polychloroprene, chlorinatedrubbers, chlorinated or sulfochlorinated polyethylene, copolymers ofethylene and chlorinated ethylene, epichlorohydrin homo- and copolymers,polymers from halogen-containing vinyl compounds,as for example,poly-vinylchloride, polyvinylidene chloride, polyvinyl fluoride,polyvinylidene fluoride, as well as copolymers thereof, as for example,vinyl chloride/vinylidene chloride, vinyl chloride/vinyl acetate orvinylidene chloride/vinyl acetate copolymers.

8. Polymers which are derived from α,β-unsaturated acids and derivativesthereof, such as polyacrylates and polymethacrylates, with butylacrylate impact resistant modified polymethyl methacrylate,polyacrylamide and polyacrylonitrile.

9. Copolymers from the monomers mentioned under 8) with each other orwith other unsaturated monomers, such as, for instance,acrylonitrile/butadiene, acrylonitrile/alkyl acrylate,acrylonitrile/alkoxyalkyl acrylate or acrylonitrile/vinyl halogenidecopolymers or acrylonitrile/alkyl methacrylate/butadiene terpolymers.

10. Polymers which are derived from unsaturated alcohols and amines, oracyl derivatives thereof or acetals thereof, such as polyvinyl alcohol,polyvinyl acetate, polyvinyl stearate, polyvinyl benzoate, polyvinylmaleate, polyvinyl butyral, polyallyl phthalate or polyallylmelamine; aswell as their copolymers with olefins mentioned in 1 ) above.

11. Homopolymers and copolymers of cyclic ethers, such as polyalkyleneglycols, polyethylene oxide, polypropylene oxide or copolymers thereofwith bis-glycidyl ethers.

12. Polyacetals, such as polyoxymethylene and those polyoxymethyleneswhich contain ethylene oxide as a comonomer; polyacetals modified withthermoplastic polyurethanes, acrylatcs or MBS.

13. Polyphenylene oxides and sulfides, and mixtures of polyphenyleneoxides with polystyrene or polyamides.

14. Polyurethanes which are derived from polyethers, polyesters orpolybutadienes with terminal hydroxyl groups on the one side andaliphatic or aromatic polyisocyanates on the other side, as well asprecursors thereof (polyisocyanates, polyols or prepolymers).

15. Polyamides and copolyamides which are derived from diamines anddicarboxylic acids and/or from aminocarboxylic acids or the corre-sponding lactams, such as polyamide 4, polyamide 6, polyamide 6/6, 6/10,6/9, 6/12, 4/6, 12/12 polyamide 11, polyamide 12, aromatic polyamidesobtained by condensation of m-xylene diamine and adipic acid; polyamidesprepared from hexamethylenediamine and isophthalic or/and terephthalicacid and optionally an elastomer as modifier, for examplepoly-2,4,4,-trimethylhexamethylene terephthalamide or poly-m-phenyleneisophthalamide. Further copolymers of the aforementioned polyamides withpolyolefins, olefin copolymers, ionomers or chemically bonded or graftedelastomers; or with polyethers, such as for instance, with polyethyleneglycols, polypropylene glycols or polytetramethylene glycols. Polyamidesor copolyamides modified with EPDM or ABS. Polyamides condensed duringprocessing (RIM-polyamide systems).

16. Polyureas, polyimides and polyamide-imides.

17. Polyesters which am derived from dicarboxylic acids and diolsandl[ch]or from hydroxycarboxylic acids or the corresponding lactones,such as polyethylene terephthalate, polybutylene terephthalate,poly-1,4-dimethylolcyclohexane terephthalate,poly-[2,2,-(4-hydroxyphenyl)- propane] terephthalate andpolyhydroxybenzoates as well as block-copolyether-esters derived frompolyethers having hydroxyl end groups.

18. Polycarbonates and polyester-carbonates.

19. Polysulfones, polyether-sulfones and polyether-ketones.

20. Crosslinked polymers which are derived from aldehydes on the onehand and phenols, ureas and melamines on the other hand, such asphenol/formaldehyde resins, urea/formaldehyde resins andmelamine/formaldehyde resins.

21. Drying and non-drying alkyd resins.

22. Unsaturated polyester resins which are derived from copolyesters ofsaturated and unsaturated dicarboxylic acids with polyhydric alcoholsand vinyl compounds as crosslinking agents, and also halogen-containingmodifications thereof of low inflammability.

23. Thermosetting acrylic resins, derived from substituted acrylicesters, such as epoxy-acrylates, urethane-acrylates orpolyester-acrylates.

24. Alkyd resins, polyester resins or acrylate resins in admixture withmelamine resins, urea resins, polyisocyanates or epoxide resins ascrosslinking agents.

25. Crosslinked epoxide resins which are derived from polyepoxides, forexample from bis-glycidyl ethers or from cycloaliphatic diepoxides.

26. Natural polymers, such as cellulose, rubber, gelatine andderivatives thereof which are chemically modified in apolymer-homologous manner, such as cellulose acetates, cellulosepropionates and cellulose butyrates, or the cellulose ethers, such asmethylcellulose; rosins and their derivatives.

27. Mixtures of polymers as mentioned above, for example PP/EPDM,Polyamide 6/EPDM or ABS, PVC/EVA, PVC/ABS, PVC/MBS, PC/ABS, PBTP/ABS,PC/ASA, PC/PBT, PVC/CPE, PVC/acrylates, POM/thermoplastic PUR,PC/thermoplastic PUR, POM/acrylate, POM/MBS, PPE/HIPS, PPE/PA 6.6 andcopolymers, PA/HDPE, PA/PP, PA/PPE.

28. Naturally occurring and synthetic organic materials which are puremonomeric compounds or mixtures of such compounds, for example mineraloils, animal and vegetable fats, oil and waxes, or oils, fats and waxesbased on synthetic esters (e.g. phthalates, adipates, phosphates ortrimellithates) and also mixtures of synthetic esters with mineral oilsin any weight ratios, which materials may be used as plasticizer forpolymers or as textile spinning oils, as well as aqueous emulsions ofsuch materials.

29. Aqueous emulsions of natural or synthetic rubber, e.g. natural latexor latices of carboxylated styrene/butadiene copolymers.

The compounds of the formula (I) are particularly suitable for improvingthe light stability, heat stability and oxidation stability ofpolyolefins, especially polyethylene and polypropylene.

The compounds of the formula (I) can be used in mixtures with organicmaterials in various proportions depending on the nature of the materialto be stabilised, on the end use and on the presence of other additives.

In general, it is appropriate to use, for example, 0.01 to 5% by weightof the compounds of the formula (I), relative to the weight of thematerial to be stabilised, preferably between 0.05 and 1%.

In general, the compounds of the formula (I) can be incorporated in thepolymeric materials before, during or after the polymerization orcrosslinking of the said materials.

The compounds of the formula (I) can be incorporated in the polymericmaterials in the pure form or encapsulated in waxes, oils or polymers.

The compounds of the formula (I) can be incorporated in the polymericmaterials by various processes, such as dry mixing in the form ofpowder, or wet mixing in the form of solutions or suspensions or also inthe form of a masterbatch; in such operations, the polymer can be usedin the form of powder, granules, solutions, suspensions or in the formof latices.

The materials stabilised with the products of the formula (I) can beused for the production of mouldings, films, tapes, monofilaments,fibres, surface coatings and the like.

If desired, other conventional additives for synthetic polymers, such asantioxidants, UV absorbers, nickel stabilisers, pigments, fillers,plasticisers, antistatic agents, flameproofing agents, lubricants,corrosion inhibitors and metal deactivators, can be added to themixtures of the compounds of the formula (I) with the organic materials.

Particular examples of additives which can be used in admixture with thecompounds of the formula (I) are:

1. Antioxidants

1.1. Alkylated monophenols, for example2,6-di-tert-butyl-4-methyl-phenol, 2-tert-butyl-4,6-dimethylphenol,2,6-di-tert-butyl-4-ethylphenol, 2,6-di-tert-butyl-4-n-butylphenol,2,6-di-tert-butyl-4-iso-butylphenol, 2,6-dicyclopentyl-4-methylphenol,2-(α-methylcyclohexyl)-4,6-dimethylphenol,2,6-dioctadecyl-4-methylphenol, 2,4,6-tricyclohexyl-phenol,2,6-di-tert-butyl-4-methoxymethylphenol, 2,6-di-nonyl-4-methylphenol,2,4-dimethyl-6-(1'-methyl-undec-1'-yl)-phenol,2,4-dimethyl-6-(1'-methyl-heptadec-1'-yl)-phenol,2,4-dimethyl-6-(1'-methyl-tridec-1'-yl)-phenol and mixtures therof.

1.2. Alkylthiomethylphenols, for example2,4-dioctylthiomethyl-6-tert-butylphenol,2,4-dioctylthiomethyl-6-methylphenol,2,4-dioctylthiomethyl-6-ethylphenol,2,6-di-do-decylthiomethyl-4-nonylphenol.

1.3. Hydroquinones and alkylated hydroquinones, for example2,6-di-tert-butyl-4-methoxy-phenol, 2,5-di-tert-butylhydroquinone,2,5-di-tert-amylhydroquinone, 2,6-di-phenyl-4-octadecyloxyphenol,2,6-di-tert-butyl-hydroquinone, 2,5-di-tert-butyl-4-hydroxyanisole,3,5-di-tert-butyl-4-hydroxyanisole,3,5-di-tert-butyl-4-hydroxy-phenyl-stearate,bis-(3,5-di-tert-butyl-4-hydroxyphenyl)adipate.

1.4. Hydroxylated thiodiphenyl ethers, for example2,2'-thiobis(6-tert-butyl-4-methylphenol), 2,2'-thiobis(4-octylphenol),4,4'-thiobis(6-tert-butyl-3-methylphenol),4,4'-thiobis(6-tert-butyl-2-methylphenol),4,4'-thio-bis-(3,6-di-sec-amylphenol),4,4'-bis-(2,6-dimethyl-4-hydroxyphenyl)-disulfide.

1.5. Alkylidenebisphenols, for example2,2'-methylenebis(6-tert-butyl-4-methylphenol),2,2'-methylenebis(6-tert-butyl-4-ethylphenol),2,2'-methylenebis[4-methyl-6-(α-methylcyclohexyl)phenol],2,2'-methylenebis(4-methyl-6-cyclohexylphenol),2,2'-methylenebis(6-nonyl-4-methylphenol),2,2'-methylenebis(4,6-di-tert-butylphenol),2,2'-ethylidenebis(4,6-di-tert-butylphenol),2,2'-ethylidenebis(6-tert-butyl-4-isobutylphenol),2,2'-methylenebis[6-(α-methylbenzyl)-4-nonylphenol],2,2'-methylenebis[6-(α,60 -dimethylbenzyl)-4-nonylphenol],4,4'-methylenebis(2,6-di-tert-butylphenol),4,4'-methylenebis(6-tert-butyl-2-methylphenol),1,1-bis(5-tert-butyl-4-hydroxy2-methylphenyl)butane,2,6-bis(3-tert-butyl-5-methyl-2-hydroxybenzyl)-4-methylphenol,1,1,3-tris(5-tert-butyl-4-hydroxy-2-methylphenyl)butane,1,1-bis(5-tert-butyl-4-hydroxy-2-methyl-phenyl)-3-n-dodecylmercaptobutane,ethylene glycol bis[3,3-bis(3'-tert-butyl-4'-hydroxyphenyl)butyrate],bis(3-tert-butyl-4-hydroxy-5-methylphenyl)dicyclopentadiene,bis[2-(3'-tert-butyl-2'-hydroxy-5'-methylbenzyl)-6-tert-butyl-4-methylphenyl]terephthalate,1,1-bis-(3,5-dimethyl-2-hydroxyphenyl)butan,2,2-bis-(3,5-di-tert.-butyl-4-hydroxyphenyl)-propan,2,2-bis-(5-tert.-butyl-4-hydroxy-2-methylphenyl)-4-n-dodecylmercapto-butan,1,1,5,5-tetra-(5-tert.-butyl-4-hydroxy-2-methylphenyl)-pentan.

1.6. O-, N- and S-benzyl compounds, for example3,5,3',5'-tetra-tert.-butyl-4,4'-dihydroxydibenzylether,octadecyl-4-hydroxy-3,5-dimethylbenzyl-mercaptoacetate,tris-(3,5-di-tert.-butyl-4-hydroxybenzyl)-amine,bis-(4-tert.-butyl-3-hydroxy-2,6-dimethylbenzyl)dithioterephthalate,bis-( 3,5-di-tert.-butyl-4-hydroxybenzyl)-sulfide,isooctyl-3,5-di-tert.-butyl-4-hydroxybenzyl-mercaptoacetate.

1.7. Hydroxybenzylated Malonates, for exampledioctadecyl-2,2-bis-(3,5-di-tert.-butyl-2-hydroxybenzyl)-malonate,di-octadecyl-2-(3-tert.-butyl-4-hydroxy-5-methylbenzyl)-malonate,di-dodecylmercaptoethyl-2,2-bis(3,5-di-tert.-butyl-4-hydroxybenzyl)-malonate,Di-[4-(1,1,3,3-tetramethylbutyl)-phenyl]-2,2-bis-(3,5-di-tert.-butyl-4-hydroxybenzyl)-malonate.

1.8. Hydroxybenzyl-Aromatics, for example1,3,5-tris-(3,5-di-tert.-butyl-4-hydroxy-benzyl)-2,4,6-trimethylbenzene,1,4-bis-(3,5-di-tert.-butyl-4-hydroxybenzyl)-2,3,5,6-tetramethylbenzene,2,4,6-tris-(3,5-di-tert.-butyl-4-hydroxybenzyl)-phenol.

1.9. Triazine Compounds, for example2,4-bis-octylmercapto-6-(3,5-di-tert.-butyl-4-hydroxyanilino)-1,3,5-triazine,2-octylmercapto-4,6-bis-(3,5-di-tert.-butyl-4-hydroxyanilino)-1,3,5-triazine,2-octylmercapto-4,6-bis-(3,5-di-tert.-butyl-4-hydroxyphenoxy) -1,3,5-triazine, 2,4,6-tris-(3,5-di-tert.-butyl-4-hydroxyphenoxy)-1,2,3-triazine,1,3,5-tris-(3,5-di-tert.-butyl-4-hydroxybenzyl)-isocyanurate,1,3,5-tris-(4-tert.-butyl-3-hydroxy-2,6-di-methylbenzyl)-isocyanurate,2,4,6-tris-(3,5-di-tert.-butyl-4-hydroxyphenylethyl)-1,3,5-triazine,1,3,5-tris-(3,5-di-tert.-butyl-4-hydroxyphenylpropionyl)-hexahydro-1,3,5-triazine,1,3,5-tris-(3,5-dicyclohexyl-4-hydroxybenzyl)-isocyanurate.

1.10. Benzylphosphonates, for exampledimethyl-2,5-di-tert.-butyl-4-hydroxybenzylphosphonate,diethyl-3,5-di-tert.-butyl-4-hydroxybenzylphosphonate,dioctadecyl-3,5-di-tert.-butyl-4-hydroxybenzylphosphonate,dioctadecyl-5-tert.-butyl-4-hydroxy-3-methylbenzylphosphonate, Ca-saltof the 3,5-di-tert.-butyl-4-hydroxybenzyl-phosphonic acidmonoethylester.

1.11. Acylaminophenols, for example lauric acid 4-hydroxyanilide,stearic acid 4-hydroxyanilide, octylN-(3,5-di-tert-butyl-4-hydroxyphenyl)-carbamate.

1.12. Esters of β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionic acid withmono- or polyhydric alcohols, e.g. with methanol, ethanol, octadecanol,1,6-hexanediol, 1,9-nonanediol, ethylene glycol, 1,2-propanediol,neopentyl glycol, thiodiethylene glycol, diethylene glycol, triethyleneglycol, pentaerythritol, tris(hydroxyethyl) isocyanurate,N,N'-bis(hydroxyethyl)oxalic acid diamide, 3-thiaundecanol,3-thiapentadecanol, trimethylhexanediol, trimethylolpropane,4-hydroxymethyl-1-phospha-2,6,7-trioxabicyclo-[2.2.2]-octane.

1.13. Esters of β-(5-tert-butyl-4-hydroxy-3-methylphenyl)propionic acidwith mono- or polyhydric alcohols, e.g. with methanol, ethanol,octadecanol, 1,6-hexanediol, 1,9-nonanediol, ethylene glycol,1,2-propanediol, neopentyl glycol, thiodiethylene glycol, diethyleneglycol, triethylene glycol, pentaerythritol, tris(hydroxyethyl)isocyanurate, N,N'-bis(hydroxyethyl)oxalic acid diamide,3-thiaundecanol, 3-thiapentadecanol, trimethylhexanediol,trimethylolpropane,4-hydroxymethyl-1-phospha-2,6,7-trioxabicyclo-[2.2.2]-octane.

1.14 Esters of β-(3,5-dicyclohexyl-4-hydroxyphenyl)propionic acid withmono- or polyhydric alcohols, e.g. with methanol, ethanol, octadecanol,1,6-hexanediol, 1,9-nonanediol, ethylene glycol, 1,2-propanediol,neopentyl glycol, thiodiethylene glycol, diethylene glycol, triethyleneglycol, pentaerythritol, tris(hydroxyethyl) isocyanurate,N,N'-bis(hydroxyethyl)oxalic acid diamide, 3-thiaundecanol,3-thiapentadecanol, trimethylhexanediol, trimethylolpropane,4-hydroxymethyl-1-phospha-2,6,7-trioxabicyclo-[2.2.2]-octane.

1.15 Esters of 3,5-di-tert.-butyl-4-hydroxyphenyl acetic acid with mono-or polyhydric alcohols, e.g. with methanol, ethanol, octadecanol,1,6-hexanediol, 1,9-nonanediol, ethylene glycol, 1,2-propanediol,neopentyl glycol, thiodiethylene glycol, diethylene glycol, triethyleneglycol, pentaerythritol, tris(hydroxyethyl) isocyanurate,N,N'-bis(hydroxyethyl)oxalic acid diamide, 3-thiaundecanol,3-thiapentadecanol, trimethylhexanediol, trimethylolpropane,4-hydroxymethyl-1-phospha-2,6,7-trioxabicyclo-[2.2.2]-octane.

1.16. Amides of 13-(3,5-di-tert-butyl-4-hydroxyphenyl)propionic acide.g. N,N'-bis(3,5-di-tert-butyl-4-hydroxyphenylpropionyl)hexamethylene-diamine,N,N'-bis(3,5-di-tert-butyl-4-hydroxyphenylpropionyl)tri-methylene-diamine,N,N'-bis(3,5-di-tert-butyl-4-hydroxyphenylpropionyl)-hydrazine.

2. UV absorbers and light stabilisers

2.1.2-(2'-Hydroxyphenyl)benzotriazoles, for example the 5'-methyl,3',5'-di-tert-butyl, 5'-tert-butyl, 5'-(1,1,3,3-tetramethylbutyl),5-chloro-3',5'-di-tert-butyl, 5-chloro-3'-tert-butyl-5'-methyl,3'-sec-butyl-5'-tert-butyl, 4'-octoxy, 3',5'-di-tert-amyl and3',5'-bis(α,α- dimethylbenzyl), mixture of5-chloro-3'-tert.-butyl-5'-(2-octyloxycarbonyl-ethyl)- and5-chloro-3'-tert.-butyl-5'-[2-(2-ethylhexyloxy)-carbonylethyl]-,5-chloro-3'-tert.-butyl-5'-(2-methoxycarbonylethyl)-,3'-tert.-butyl-5'-(2-methoxycarbonylethyl)-,3'-tert.-butyl-5'-(2-octyloxycarbonylethyl)-,3'-tert.-butyl-5'-[2-(2-ethylhexyloxy)carbonylethyl]-,3'-dodecyl-5'-methyl- and3'-tert.-butyl-5'-(2-isooctyloxycarbonylethyl)-2'-hydroxyphenyl-2H-benztriazole(2),2,2'-methylene-bis[4-(1,1,3,3-tetramethylbutyl)-6-benztriazole-2-yl-phenol];product of ester interchange of2-[3'-tert.-butyl-5'-(2-methoxycarbonylethyl)-2'-hydroxy-phenyl]-2H-benztriazolewith polyethylene glycol 300; [R-CH₂ CH₂ --COO(CH₂)₃ ]₂ withR=3'-tert.-butyl-4'-hydroxy-5'-2H-benzotriazole-2-yl-phenyl.

2.2. 2-Hydroxybenzophenones, for example the 4-hydroxy, 4-methoxy,4-octoxy, 4-decyloxy, 4-dodecyloxy, 4-benzyloxy, 4,2',4'-trihydroxy and2'-hydroxy-4,4'-dimethoxy derivatives.

2.3. Esters of substituted and unsubstituted benzoic acids, as forexample 4-tert.butylphenyl salicylate, phenyl salicylate, octylphenylsalicylate, dibenzoylresorcinol, bis-(4-tert.butylbenzoyl)-resorcinol,benzoylresorcinol, 2,4-di-tert.butylphenyl3,5-di-tert.butyl-4-hydroxybenzoate, hexadecyl 3,5-di-tert.butyl-4-hydroxybenzoate, octadecyl 3,5-di-tert.-butyl-4-hydroxybenzoate,2 methyl-4,6-di-tert.-butylphenyl 3,5-di-tert.-butyl-4-hydroxybenzoate.

2.4. Acrylates, for example ethyl α-cyano-β,β-diphenylacrylate, isooctylα-cyano-β,β-diphenylacrylate, methyl α-carbomethoxycinnamate, methylα-cyano-β-methyl-p-methoxy-cinnamate, butylα-cyano-β-methyl-p-methoxy-cinnamate, methylα-carbomethoxy-p-methoxycinnamate andN-(β-carbomethoxy-β-cyanovinyl)-2-methylindoline.

2.5. Nickel compounds, for example nickel complexes of2,2'-thio-bis-[4-(1,1,3,3-tetramethylbutyl)phenol], such as the 1:1 or1:2 complex, with or without additional ligands such as n-butylamine,triethanolamine or N-cyclohexyldiethanolamine, nickeldibutyldithiocarbamate, nickel salts of4-hydroxy-3,5-di-tert-butylbenzyl-phosphonic acid monoalkyl esters, e.g.of the methyl or ethyl ester, nickel complexes of ketoximes, e.g. of2-hydroxy-4-methyl-phenyl undecyl ketoxime, nickel complexes of1-phenyl-4-1auroyl-5-hydroxypyrazole, with or without additionalligands.

2.6. Sterically hindered amines, for examplebis(2,2,6,6-tetramethyl-piperidyl) sebacate,bis-(2,2,6,6-tetramethyl-piperidyl) succinate,bis(1,2,2,6,6-pentamethylpiperidyl) sebacate,bis(1,2,2,6,6-pentamethylpiperidyl)n-butyl-3,5-di-tert-butyl-4-hydroxy-benzylmalonate, the condensationproduct of 1-(2-hydroxyethyl)-2,2,6,6-tetramethyl-4-hydroxypiperidineand succinic acid, the condensation product ofN,N'-bis(2,2,6,6-tetramethyl-4-piperidyl)-hexamethylenediamine and4-tert-octylamino-2,6-dichloro-1,3,5-triazine,tris(2,2,6,6-tetramethyl-4-piperidyl) nitrilotriacetate,tetrakis(2,2,6,6-tetramethyl-4-piperidyl)-1,2,3,4-butane-tetracarboxylate,1,1'-(1,2-ethanediyl)bis-(3,3,5,5-tetramethylpiperazinone),4-benzoyl-2,2,6,6-tetramethylpiperidine,4-stearyloxy-2,2,6,6-tetramethylpiperidine,bis-(1,2,2,6,6-pentamethylpiperidyl)-2-n-butyl-2-(2-hydroxy-3,5-di-tert.-butylbenzyl)malonate, 3-n-octyl-7,7,9,9-tetramethyl-1,3,8-triazasprio[4.5]decan-2,4-dion,bis-(1-octyloxy-2,2,6,6-tetramethylpiperidyl) sebacate,his-(1-octyloxy-2,2,6,6-tetramethylpiperidyl) succinate, product ofcondensation of N,N'-bis-(2,2,6,6-tetramethyl4-piperidyl)-hexamethylenediamine and 4-morpholino-2,6-dichloro-1,3,5-triazine, product ofcondensation ofchloro-4,6-di-(4-n-butylamino-2,2,6,6-tetramethylpiperidyl)-1,3,5-triazineand 1,2-bis-(3-aminopropylamino)ethane, product of condensation of2-chloro-4,6-di-(4-n-butylamino- 1,2,2,6,6-pentamethylpiperidyl)-1,3,5-triazine and 1,2-bis-(3-aminopropylamino)ethane,8-acetyl-3-dodecyl-7,7,9,9-tetramethyl-1,3,8-triazaspiro[4.5]decane-2,4-dion, 3-dodecyl-1-(2,2,6,6-tetramethyl-4-piperidyl)pyrrolidin2,5-dion, 3-dodecyl-1-(1,2,2,6,6-pentamethyl-4-piperidyl)-pyrrolidin-2,5-dion.

2.7. Oxalic acid diamides, for example 4,4'-dioctyloxyoxanilide,2,2'-dioctyloxy-5,5'-di-tert-butyloxanilide,2,2'-didodecyloxy-5,5'-di-tert-butyloxanilide,2-ethoxy-2'-ethyloxanilide, N,N'-bis(3-dimethylamino-propyl)oxalamide,2-ethoxy-5-tert-butyl-2'-ethyloxanilide and its mixture with2-ethoxy-2'-ethyl-5,4'-di-tert-butyloxanilide and mixtures of ortho- andpara-methoxy-disubstituted oxanilides and mixtures of o- andp-ethoxy-disubstituted oxanilides.

2.8.2-(2-Hydroxyphenyl)-1,3,5-triazines, for example2,4,6-tris(2-hydroxy-4-octyloxy-phenyl)-1,3,5-triazine,2-(2-hydroxy-4-octyloxy-phenyl)-4,6-bis(2,4-dimethylphenyl)-1,3,5-triazine,2-(2,4-dihydroxy-phenyl)-4,6-bis(2,4-dimethylphenyl)-1,3,5-triazine,2,4-bis(2-hydroxy-4-propyloxyphenyl)-6-(2,4-dimethylphenyl)-1,3,5-triazine,2-(2-hydroxy-4-octyloxyphenyl)-4,6-bis(4-methylphenyl)-1,3,5- triazine,2-(2-hydroxy-4-dodecyloxyphenyl)-4,6-bis(2,4-dimethylphenyl)-1,3,5-triazine,2-[2-hydroxy-4-(2-hydroxy-3-butyloxy-propyloxy)phenyl]-4,6-bis(2,4-dimethyl)-1,3,5-triazine,2-[2-hydroxy-4-(2-hydroxy-3-octyloxy-propyloxy)phenyl]-4,6-bis(2,4-dimethyl)-1,3,5-triazin

3. Metal deactivators, for example N,N'-diphenyloxalic acid diamide,N-salicylal-N'-salicyloylhydrazine, N,N'-bis(salicyloyl)hydrazine,N,N'-bis(3,5-di-tert-butyl-4hydroxyphenylpropionyl)hydrazine,3-salicyl-oylamino-1,2,4-triazole, bis(benzylidene)oxalodihydrazide,Oxanilide, isophthalic acid dihydrazide, sebacicacid-bis-phenylhydrazide, N,N'-diacetal-adipinic acid dihydrazide,N,N'-bis-salicyloyl-oxalic acid dihydrazide,N,N'-bis-salicyloyl-thiopropionic acid dihydrazide.

4. Phosphites and phosphonites, for example triphenyl phosphite,diphenyl alkyl phosphites, phenyl dialkyl phosphites, tris(nonylphenyl)phosphite, trilauryl phosphite, trioctadecyl phosphite, distearylpentaerythritol diphosphite, tris(2,4-di-tert-butylphenyl) phosphite,diiso- decyl pentaerythritol diphosphite, bis(2,4-di-tert.-butylphenyl)pentaerythritol diphosphite,bis-(2,6-di-tert.-butyl-4-methylphenyl)-pentaerythritol diphosphite,bis-isodecyloxy-pentaerythritol diphosphite,bis-(2,4-di-tert.-butyl-6-methylphenyl)-pentaerythritol diphosphite,bis-(2,4,6-tri-tert.-butylphenyl)-pentaerythritol diphsophite,tristearyl sorbitol triphosphite, tetrakis(2,4-di-tert-butylphenyl)4,4'-biphenylene diphosphonite,6-isooctyloxy-2,4,8,10-tetra-tert.-butyl-12H-dibenz[d,g]-1,3,2-dioxaphosphocin, 6-fluoro-2,4,8,10-tetra-tert.-butyl- 12-methyl-dibenz[d,g]-1,3,2-dioxaphosphocin.

4a. Hydroxylamines, for example dibenzylhydroxylamine,dioctylhydroxylamine, didodecylhydroxylamine, ditetradecylhydroxylamine,dihexadecylhydroxylamine, dioctadecylhydroxylamine,1-hydroxy-2,2,6,6-tetramethyl-4-piperidyl benzoate orbis(1-hydroxy-2,2,6,6-tetramethyl-4-piperidyl) sebacate.

5. Peroxide scavengers, for example esters of β-thiodipropionic acid,for example the lauryl, stearyl, myristyl or tridecyl esters,mercaptobenzimidazole or the zinc salt of 2-mercaptobenzimidazole, zincdibutyldithiocarbamate, dioctadecyl disulfide, pentaerythritoltetrakis(p-dodecyl-mercapto )propionate.

6. Polyamide stabilisers, for example, copper salts in combination withiodides and/or phosphorus compounds and salts of divalent manganese.

7. Basic co-stabilisers, for example, melamine, polyvinylpyrrolidone,dicyandiamide, triallyl cyanurate, urea derivatives, hydrazinederivatives, amines, polyamides, polyurethanes, alkali metal salts andalkaline earth metal salts of higher fatty acids for example Castearate, Zn stearate, Mg behenate, Mg stearate, Na ricinoleate and Kpalmirate, antimony pyrocatecholate or zinc pyrocatecholate.

8. Nucleating agents, for example, 4-tert.butyl-benzoic acid, adipicacid, diphenylacetic acid.

9. Fillers and reinforcing agents, for example, calcium carbonate,silicates, glass fibres, asbestos, talc, kaolin, mica, barium sulfate,metal oxides and hydroxydes, carbon black, graphite.

10. Other additives, for example, plasticisers, lubricants, emulsifiers,pigments, optical brighteners, flameproofing agents, antistatic agentsand blowing agents.

The compounds of the formula (I) can also be used as stabilisers,especially as light stabilisers, for almost all materials known in theart of photographic reproduction and other reproduction techniques ase.g. described in Research Disclosure 1990, 31429 (pages 474 to 480).

Several examples of the preparation and use of the compounds of theformula (I) are reported for more detailed illustration of the presentinvention; these examples are given solely for illustrative purposes anddo not imply any restriction.

The compounds of Examples 1, 2, 4, 5 and 6 pertain to a particularlypreferred embodiment of the instant invention.

Preparation ofN,1-bis(2,2,6,6-tetramethyl-4-piperidyl)-4-piperidinemethanamine: 223.5g (1.44 tool) of 2,2,6,6-tetramethyl-4-piperidone, 82.2 g (0.72 tool) of4-piperidinemethanamine, 0.2 g of benzoic acid and 500 ml of toluene areheated under reflux with azeotropic removal of the water of reaction.

The solvent is removed by heating to 50° C. in vacuo and the residueobtained is dissolved in 800 ml of methanol and hydrogenated at ambienttemperature in the presence of 12 g of 5% Pt on carbon under a hydrogenpressure of 40 bar.

After separating off the catalyst by filtration, the solvent isevaporated in vacuo and the residue is crystallised from acetonitrile.

The product obtained melts at 91°-93° C.

Analysis for C₂₄ H₄₈ N₄

Calculated: C=73.41%; H=12.32%; N=14.27%

Found: C=72.80%; H=12.26%; N=14.15%

EXAMPLE 1

Preparation of the Compound of the Formula ##STR51##

19.6 g (0.05 tool)ofN,l-bis(2,2,6,6-tetramethyl-4-piperidyl)-4-piperidinemethanamine aredissolved at ambient temperature in a solution of 20.7 g (0.45 tool) offormic acid in 250 ml of water.

13.5 g (0.45 mol) of paraformaldehyde are added to the solution obtainedand the mixture is heated under reflux for 8 hours. After cooling toambient temperature, a solution of 20 g of sodium hydroxide in 120 ml ofwater is added; a precipitate forms, which is extracted withdichloromethane.

The organic phase is then separated off, washed with water and driedover Na₂ SO₄.

Evaporation of the solvent gives a low-melting residue.

Analysis for C₂₇ H₅₄ N₄

Calculated: C=74.59%; H=12.52%; N=12.89%

Found: C=74.57%; H=12.50%; N=12.81%

EXAMPLE 2

Preparation of the Compound of the Formula ##STR52##

A solution of 9.1 g (0.056 mol) of octanoyl chloride in 20 ml ofdichloromethane is added slowly to a solution, cooled to 10° C., of 22 g(0.056 mol) ofN,1-bis(2,2,6,6-tetramethyl-4-piperidyl)-4-piperidinemethanamine in 100ml of dichloromethane.

The solution is then stirred for 2 hours at ambient temperature.

A solution of 2.4 g (0.06 tool) of sodium hydroxide in 50 ml of water isadded slowly, while maintaining the temperature at 10° C., and themixture is stirred for 1 hour at ambient temperature. The organic phaseis then separated off, washed with water and dried over Na₂ SO₄. Alow-melting residue is obtained by evaporation of the solvent.

Analysis for C₃₂ H₆₂ N₄ O

Calculated: C=74.08%; H=12.04%; N=10.80%

Found: C=73.48%; H=11.98%; N=10.67%

EXAMPLE 3

Preparation of the Compound of the Formula ##STR53##

58.9 g (0.15 mol) of N,1-bis(2,2,6,6-tetramethyl-4-piperidyl)-4-piperidinemethanamine,dissolved in 100 ml of mesitylene, are added slowly to a solution of 9.2g (0.05 mol) of cyanuric chloride in 100 ml of mesitylene, whilemaintaining the temperature at 20° C.

After the end of the addition, the mixture is heated for 4 hours at 60°C; 8 g (0.2 mol) of powdered sodium hydroxide are added and the mixtureis heated for 10 hours under reflux, with azeotropic removal of thewater of reaction.

After cooling to 60° C., the mixture is filtered and evaporated under areduced pressure.

The residue is then crystallised from a 1:1 acetonitrile/water mixture.The product obtained melts at 165°-166° C.

Analysis for C₇₅ H₁₄₁ N₁₅

Calculated: C=71.89 %; H=11.34 %; N=16.77%

Found: C=71.30%; H=11.24%; N=16.58%

EXAMPLE 4

Preparation of the Compound of the Formula ##STR54##

A) Preparation of 2-chloro-4,6-bis[N,1-bis(2,2,6,6-tetramethyl-4-piperidyl)-4-piperidinemethanamino]-1,3,5-triazine.

A solution of 46.1 g (0.25 tool) of cyanuric chloride in 500 ml ofxylene is added slowly to a solution of 196.3 g (0.5 tool) ofN,1-bis(2,2,6,6-tetramethyl-4-piperidyl)-4-piperidinemethanamine in 400ml of xylene, while maintaining the temperature between 20° and 50° C.

The mixture is then stirred for one hour at ambient temperature, 20 g(0.5 mol) of sodium hydroxide dissolved in 100 ml of water are added andthe mixture is heated for 2 hours at 100° C.

After cooling to ambient temperature, the aqueous phase is separatedoff, and the organic layer is dried over Na2SO₄, filtered and evaporatedunder a reduced pressure.

The residue thus obtained is crystallised from a 5:1 ethyl acetate/watermixture. The product obtained melts at 135°-137° C.

Cl=3.96 % (calculated for C₅₁ H₉₄ ClN₁₁ =3.95%)

B) 29.6 g (0.033 mol) of 2-chloro-4,6-bis[N,1-bis(2,2,6,6-tetramethyl-4-piperidyl)-4-piperidinemethanamino]-1,3,5-triazine,6.3 g (0.016 mol)ofN,N'-bis(2,2,6,6-tetramethyl-4-piperidyl)-1,6-hexanediamine and 2.6 g(0.066 mol) of powdered sodium hydroxide in 200 ml of mesitylene areheated under reflux for 10 hours with azeotropic removal of the water ofreaction.

After cooling to 70° C., the reaction mixture is filtered and evaporatedunder a reduced pressure.

The residue is crystallised from acetonitrile.

The product obtained melts at 172°-175° C.

Analysis for C₁₂₆ H₂₃₆ N₂₆

Calculated: C=7 1.54%; H=11.24 %; N=17.22%

Found: C=7 1.23%; H=10.76 %; N=17.09%

EXAMPLES 5-6

Following the procedure described in Example 4 and using thecorresponding reagents in the appropriate molar ratios, the followingcompounds of the formula ##STR55## are prepared.

    __________________________________________________________________________    Example                                                                            n R                        m.p. (°C.)                             __________________________________________________________________________    5    3                                                                                ##STR56##               182-183                                       6    4                                                                                ##STR57##               186-188                                       __________________________________________________________________________

EXAMPLE 7

Preparation of the Compound of the Formula ##STR58##

A mixture containing 4.6 g (0.1 mol) of formic acid and 10 g (0.1 mol)of a methanol-free aqueous 30% formaldehyde solution is added in thecourse of 3 hours to a solution of 18.8 g (0.015 tool) of the compoundprepared according to Example 4 in 100 ml of xylene, heated to 110° C.,with simultaneous removal of the water added and the water of reaction.

The mixture is then cooled to 70° C., a solution of 6 g of sodiumhydroxide in 50 ml of water is added and the mixture is stirred for 30minutes. After separating off the aqueous phase, the organic layer iswashed with water, dried over Na₂ SO₄ and evaporated under a reducedpressure.

The product obtained melts at 174°-176° C.

Analysis for C₈₁ H₁₅₃ N₁₅

Calculated: C=72.76%; H=11.53%; N=15.71%

Found: C=72.38%; H=11.51%; N=15.53%

EXAMPLES 8-9

Following the procedure described in Example 7 and using the compoundsfrom Examples 5 and 6, the following compounds of the formula ##STR59##are prepared.

    __________________________________________________________________________    Example                                                                            n R                           m.p. (°C.)                          __________________________________________________________________________    8    2                                                                                ##STR60##                  192-195                                    9    3                                                                                ##STR61##                  185-187                                    __________________________________________________________________________

EXAMPLE 10

Light-Stabilising Action in Polypropylene Tapes.

1 g of each of the compounds indicated in Table 1, 1.0 g oftris(2,4-di-t-butylphenyl) phosphite, 0.5 g of pentaerythritoltetrakis[3-(3,5-di-t-butyl-4-hydroxyphenyl)-propionate] and 1 g ofcalcium stearate are mixed in a slow mixer with 1000 g of polypropylenepowder of melt index=2 g/10 minutes (measured at 230° C. and 2.16 kg).

The mixtures are extruded at 200°-230° C. to give polymer granules whichare then convened into stretched tapes of 50 μm thickness and 2.5 mmwidth, using a pilot-type apparatus (®Leonard-Sumirago (VA) Italy)operating under the following conditions:

Extruder temperature: 210°-230° C.

Head temperature: 240°-260° C.

Stretch ratio: 1:6

The tapes thus prepared are exposed, mounted on a white card, in a 65 WRWeather-O-Meter (ASTM D2565-85) with a black panel temperature of 63° C.

The residual tenacity is measured on samples taken after various timesof exposure to light by means of a constant-speed tensometer; theexposure time in hours (T₅₀) needed to halve the initial tenacity isthen calculated.

Tapes prepared under the same conditions as indicated above, but withoutaddition of stabilisers according to the present invention, are exposedfor comparison.

The results obtained are shown in Table 1.

                  TABLE 1                                                         ______________________________________                                        Stabiliser          T.sub.50 (hours)                                          ______________________________________                                        None                 530                                                      Compound from Example 1                                                                           3950                                                      Compound from Example 2                                                                           3500                                                      Compound from Example 4                                                                           3930                                                      Compound from Example 5                                                                           3500                                                      ______________________________________                                    

EXAMPLE 11

Light-Stabilising Action in Polypropylene Fibres.

2.5 g of each of the products indicated in Table 2, 1 g oftris(2,4-di-t-butylphenyl) phosphite, 0.5 g of calcium monoethyl3,5-di-t-butyl-4-hydroxybenzylphosphonate, 1 g of calcium stearate and2.5 g of titanium dioxide are mixed in a slow mixer with 1000 g ofpolypropylene powder of melt index=12 g/10 minutes (measured at 230° C.and 2.16 kg).

The mixtures are extruded at 200°-230° C. to give polymer granules whichare then converted into fibres, using a pilot-type apparatus(®Leonard-Sumirago (VA) Italy) operating under the following conditions:

Extruder temperature: 200°-230° C.

Head temperature: 255°-260° C.

Stretch ratio: 1:3.5

Count: 11 dtex per filament.

The fibres thus prepared are exposed, after mounting on a white card, ina model 65 WR Weather-0-Meter (ASTM D2565-85) with a black paneltemperature of 63° C.

The residual tenacity is measured on samples taken after various timesof exposure to light by means of a constant-speed tensometer, and theexposure time in hours (T₅₀) needed to halve the initial tenacity isthen calculated. Fibres prepared under the same conditions as indicatedabove, but without addition of stabilisers according to the invention,are exposed for comparison.

The results obtained are shown in Table 2.

                  TABLE 2                                                         ______________________________________                                        Stabiliser          T.sub.50 (hours)                                          ______________________________________                                        None                 170                                                      Compound from Example 5                                                                           1700                                                      Compound from Example 8                                                                           1600                                                      ______________________________________                                    

What is claimed is:
 1. A compound of formula (I) ##STR62## in which R₁is hydrogen, C₁ -C₈ alkyl, O, OH, NO, CH₂ CN, C₁ -C₁₈ alkoxy, C₅ -C₁₂cycloalkoxy, C₃ -C₆ alkenyl, C₇ -C₉ phenylalkyl which is unsubstitutedor mono-, di- or tri-substituted on the phenyl by C₁ -C₄ alkyl; or R₁ isC₁ -C₈ acyl;n is 1, 2, 3 or 4; when n is 1, A is C₁ -C₁₈ alkyl, C₃ -C₆alkenyl, C₇ _(C) ₉ phenylalkyl which is unsubstituted or mono-, di- ortri-substituted on the phenyl by C₁ -C₄ alkyl; or A is also one of thegroups of the formulae (IIa)-(IIc) ##STR63## in which X₁ and X₂ whichcan be identical or different are a group --OR₄, --SR₄ or ##STR64##where R₄, R₅ and R₆ which can be identical or different are hydrogen, C₁-C₁₈ alkyl, C₅ -C₁₂ cycloalkyl which is unsubstituted or mono-, di- ortri-substituted by C₁ -C₄ alkyl; C₃ -C₁₈ alkenyl, phenyl which isunsubstituted or mono-, di- or tri-substituted by C₁ -C₄ alkyl or C₁ -C₄alkoxy; C₇ -C₉ phenylalkyl which is unsubstituted or mono-, di- ortri-substituted on the phenyl by C₁ -C₄ alkyl; C₂ -C₄ alkyl substitutedin the 2-, 3- or 4-position by OH, by C₁ -C₈ alkoxy, by di(C₁ -C₄alkyl)amino or by 1-pyrrolidyl, 1-piperidyl, 4-morpholinyl,4-methyl-1-piperazinyl or 1-hexahydroazepinyl; tetrahydrofurfuryl or agroup of the formula (III) ##STR65## where R₇ is as defined for R₁ ; or##STR66## is 1-pyrrolidyl, 1-piperidyl, 4-morpholinyl,4-methyl-1-piperazinyl or 1-hexahydroazepinyl; R₂ is hydrogen, C₁ -C₁₈alkyl, C₅ -C₁₂ cycloalkyl which is unsubstituted or mono-, di- ortri-substituted by C₁ -C₄ alkyl; C₂ -C₁₈ alkenyl, phenyl which isunsubstituted or mono-, di- or tri-substituted by C₁ -C₄ alkyl or C₁ -C₄alkoxy and/or monosubstituted by an OH group; C₇ -C₉ phenylalkyl whichis unsubstituted or mono-, di- or tri-substituted on the phenyl by C₁-C₄ alkyl and/or monosubstituted by an OH group; p is zero or 1; R₃ isC₁ -C₁₈ alkyl, C₅ -C₁₂ cycloalkyl which is unsubstituted or mono-, di-or tri-substituted by C₁ -C₄ alkyl; C₃ -C₁₈ alkenyl, C₇ -C₉ phenylalkylwhich is unsubstituted or mono-, di- or tri-substituted on the phenyl byC₁ -C₄ alkyl; or a group of the formula (III); when n is 2, A is C₂ -C₁₂alkylene, C₄ -C₁₂ alkylene interrupted by 1, 2 or 3 oxygen atoms;2-hydroxytrimethylene, phenylenedimethylene or one of the groups of theformulae (Va)-(Ve) ##STR67## in which X₃ is as defined above for X₁ andX₂ ; or X₃ is a group of the formula (VI) ##STR68## with R₁ being asdefined above; E₁ is one of the groups of the formulae (VIIa)-(VIIb)##STR69## in which G₁, G₂ and G₃ which can be identical or different are--O--or ##STR70## where R₁₄ is hydrogen, C₁ -C₁₈ alkyl, C₅ -C₁₂cycloalkyl which is unsubstituted or mono-, di- or tri-substituted by C₁-C₄ alkyl; C₇ -C₉ phenylalkyl which is unsubstituted or mono-, di- ortri-substituted on the phenyl by C₁ -C₄ alkyl; or a group of the formula(III); R₁₀ is C₂ -C₁₂ alkylene, C₄ -C₁₂ alkylene interrupted by 1, 2 or3 oxygen atoms or by 1 or 2 ##STR71## groups where R₅ is as definedabove for R₁₄ or is C₁ 1∝C₈ acyl or (C₁ -C₈ alkoxy)carbonyl; C₅ -C₇cycloalkylene, C₅ -C₇ cycloalkylenedi(C₁ -C₄ alkylene), C₁ -C₄alkylenedi(C₅ -C₇ cycloalkylene), C₂ -C₄ alkylidenedi(C₅ -C₇cycloalkylene), phenylene, phenylenedi(C₁ -C₄ alkylene), C₁ -C₄alkylenediphenylene or C₂ -C₄ alkylidenediphenylene; R₁₁ is C₂ -C₆alkylene; G₄ is one of the groups >N--(R₁₁ -G₃)_(s) --, >CH--O-- or##STR72## with R₁₄ being as defined above; r and s which can beidentical or different are zero or 1; R₁₂ is hydrogen or, when r is 1and G₄ is >CH--O--, R₁₂ is also methyl;R₈ is a direct bond, C₁ -C₁₂alkylene, C₂ -C₄ alkenylene, cyclohexylene, cyclohexenylene orphenylene; R₉ is C₂ -C₁₂ alkylene, C₄ -C₁₂ alkylene interrupted by 1, 2or 3 oxygen atoms; C₅ -C₇ cycloalkylene, C₅ -C₇ cycloalkylenedi(C₁ -C₄alkylene) or C₂ -C₄ alkylidenedi(C₅ -C₇ cycloalkylene); q is zero or aninteger from 1 to 10; when n is 3, A is aliphatic C₄ -C₁₈ triacyl,aromatic C₉ -C₁₈ triacyl or a group of the formula (VIII) ##STR73## inwhich X₃ is as defined above; E₂ is one of the groups of the formulae(IXa)-(IXc) ##STR74## in which G₅, G₆ and G₇ which can be identical ordifferent are as defined above for G₁, G₂ and G₃ ; R₁₆, R₁₇ and R₁₈which can be identical or different are C₂ -C₆ alkylene; t is zero or 1;R₁₉, R₂₀ and R₂₁ which can be identical or different are as definedabove for R₁₄ ; G₈ is a direct bond or --CH₂ --; u and v which can beidentical or different are integers from 2 to 6; R₂₂ is C₃ -C₁₂alkanetriyl; when n is 4, A is aliphatic C₆ -C₁₈ tetraacyl, aromatic C₁₀-C₁₈ tetraacyl or a group of the formula (Xa) ##STR75## in which X₃ isas defined above; E₃ is a group of the formulae (XIa)--(XIc) ##STR76##in which G₉ is as defined above for G₁, G₂ and G₃ ; R₂₃ and R₂₄ whichcan be identical or different are C₂ -C₆ alkylene; w is zero or 1; andR₂₅ is C₄ -C₁₂ alkanetetrayl.
 2. A compound of formula (I) according toclaim 1, in which R₁ and R₇ which can be identical or different arehydrogen, C₁ -C₄ alkyl, OH, C₆ -C₁₂ alkoxy, C₅ -C₈ cycloalkoxy, allyl,benzyl or acetyl.
 3. A compound of formula (I) according to claim 1, inwhich n is 1, 2, 3 or 4;when n is 1, A is C₁ -C₁₈ alkyl, C₃ -C₄ alkenyl,benzyl which is unsubstituted or mono-, di- or tri-substituted on thephenyl by C₁ -C₄ alkyl; or A is one of the groups of the formulae(IIa)-(IIc) in which X₁ and X₂ which can be identical or different are agroup --OR₄, --SR₄ or ##STR77## where R₄, R₅ and R₆ which can beidentical or different are hydrogen, C₁ -C₁₈ alkyl, C₅ -C₈ cycloalkylwhich is unsubstituted or mono-, di- or tri-substituted by C₁ -C₄ alkyl;C₃ -C₁₈ alkenyl, phenyl which is unsubstituted or mono-, di- ortri-substituted by C₁ -C₄ alkyl or C₁ -C₄ alkoxy; benzyl which isunsubstituted or mono-, di- or tri-substituted on the phenyl by C₁ -C₄alkyl; C₂ -C₃ alkyl substituted in the 2- or 3-position by OH, by C₁ -C₄alkoxy, by di(C₂ -C₄ alkyl)amino or by a group ##STR78## where X is adirect bond, --O--, --CH₂ -- or --CH₂ CH₂ --; tetrahydrofurfuryl or agroup of the formula (III), or the group ##STR79## is a group ##STR80##as defined above; R₂ is hydrogen, C₁ -C₁₇ alkyl, C₅ -C₈ cycloalkyl whichis unsubstituted or mono-, di- or tri-substituted by C₁ -C₄ alkyl; C₂-C₁₇ alkenyl, phenyl which is unsubstituted or mono-, di- ortri-substituted by C₁ -C₄ alkyl or C₁ -C₄ alkoxy and/or monosubstitutedby an OH group; benzyl or phenylethyl which, both, are unsubstituted ormono-, di- or tri-substituted on the phenyl by C₁ -C₄ alkyl and/ormonosubstituted by an OH group; p is zero or 1; R₃ is C₁ -C₁₈ alkyl, C₅-C₁₈ cycloalkyl which is unsubstituted or mono-, di- or tri-substitutedby C₁ -C₄ alkyl; C₃ -C₁₈ alkenyl, benzyl which is unsubstituted ormono-, di- or tri-substituted on the phenyl by C₁ -C₄ alkyl; or a groupof the formula (III); when n is 2, A is C₂ -C₁₀ alkylene, C₄ -C₁₀alkylene interrupted by 1, 2 or 3 oxygen atoms; 2-hydroxytrimethylene,phenylenedimethylene or one of the groups of the formulae (Va)-(Ve) inwhich X₃ is as defined above for X₁ and X₂ or is a group of the formula(VI); E₁ is one of the groups of the formulae (VIIa)-(VIIb) in which G₁,G₂ and G₃ which can be identical or different are --O-- or ##STR81##where R₁₄ is hydrogen, C₁ -C₁₈ alkyl, C₅ -C₈ cycloalkyl which isunsubstituted or mono-, di- or tri-substituted by C₁ -C₄ alkyl; benzylwhich is unsubstituted or mono-, di- or tri-substituted on the phenyl byC₁ -C₄ alkyl; or a group of the formula (III); R₁₀ is C₂ -C₁₀ alkylene,C₄ -C₁₀ alkylene interrupted by 1, 2 or 3 oxygen atoms or by 1 or 2##STR82## groups where R₁₅ is as defined above for R₁₄ or is C₁ -C₆ acylor(C₁ -C₆ alkoxy)carbonyl; cyclohexylene, cyclohexylenedimethylene,methylenedicyclohexylene, isopropylidenedicyclohexylene, phenylene,phenylenedimethylene, methylenediphenylene, orisopropylidenediphenylene; R₁₁ is C₂ -C₄ alkylene; G₄ is >N--(R₁₁-G₃)_(s) --, >CH--O-- or ##STR83## with R₁₄ being as defined above; rand s which can be identical or different are zero or 1; R₁₂ is hydrogenor, when r is 1 and G₄ is >CH--O--, R₁₂ is also methyl; R₈ is a directbond, C₁ -C₁₀ alkylene, vinylene, cyclohexylene or phenylene; R₉ is C₂-C₁₀ alkylene, C₄ -C₁₀ alkylene interrupted by 1, 2 or 3 oxygen atoms;cyclohexylene, cyclohexylenedimethylene orisopropylidenedicyclohexylene; q is zero or an integer from 1 to 5; whenn is 3, A is aliphatic C₄ -C₁₂ triacyl, aromatic C₉ -C₁₂ triacyl or agroup of the formula (VIII) in which X₃ is as defined above and E₂ isone of the groups of the formulae (IXa)--(IXc) in which G₅, G₆ and G₇which can be identical or different are as defined above for G₁, G₂ andG₃ ; R₁₆, R₁₇ and R₁₈ which can be identical or different are C₂ -C₆alkylene; t is zero or 1; R₁₉, R₂₀ and R₂₁ which can be identical ordifferent are as defined above for R₁₄ ; G₈ is a direct bond or --CH₂--; u and v which can be identical or different are integers from 2 to6; and R₂₂ is C₃ -C₁₀ alkanetriyl; when n is 4, A is aliphatic C₆ -C₁₂tetraacyl, aromatic C₁₀ -C₁₂ tetraacyl or a group of the formula (Xa) inwhich X₃ is as defined above and E₃ is a group of the formula(XIa)-(XIc) in which G₉ is as defined above for G₁, G₂ and G₃ ; R₂₃ andR₂₄ which can be identical or different are C₂ -C₆ alkylene; w is zeroor 1; and R₂₅ is C₄ -C₈ alkanetetrayl.
 4. A compound of formula (I)according to claim 1, in which n is 1, 2, 3 or 4;when n is 1, A ismethyl, C₄ -Q₁₈ alkyl, allyl, benzyl or one of the groups of theformulae (IIa)-(IIc) in which X₁ and X₂ which can be identical ordifferent are a group --OR₄, --SR₄ or ##STR84## where R₄, R₅ and R₆which can be identical or different are hydrogen, C₁ -C₁₂ alkyl,cyclohexyl which is unsubstituted or mono-, di- or tri-substituted by C₁-C₄ alkyl; allyl, undecenyl, phenyl, benzyl, C₂ -C₃ alkyl substituted inthe 2- or 3-position by OH, by C₁ -C₄ alkoxy, by dimethylamino, bydiethylamino or by 4-morpholinyl; tetrahydrofurfuryl or a group of theformula (III), or the group ##STR85## is 4-morpholinyl; R₂ is C₂ -C₇alkyl, cyclohexyl which is unsubstituted or mono-, di- ortri-substituted by C₁ -C₄ alkyl; C₂ -C₁₀ alkenyl, phenyl, t-butylphenyl,3,5-di-t-butyl-4-hydroxyphenyl, benzyl or2-(3,5-di-t-butyl-4-hydroxyphenyl)-ethyl; p is zero or 1; R₃ is C₂ -C₁₈alkyl, cyclohexyl which is unsubstituted or mono-, di- ortri-substituted by C₁ -C₄ alkyl; allyl, undecenyl, oleyl, benzyl or agroup of the formula (III); when n is 2, A is C₂ -C₈ alkylene, C₄ -C₈alkylene interrupted by 1 or 2 oxygen atoms; 2-hydroxytrimethylene,phenylenedimethylene or one of the groups of the formulae (Va)-(Ve) inwhich X₃ is as defined above for X₁ and X₂ or is a group of the formula(VI); E₁ is one of the groups of the formulae (VIIa)-(VIIb) in which G₁,G₂ and G₃ which can be identical or different are --O-- or ##STR86##where R₁₄ is hydrogen, C₁ -C₁₂ alkyl, cyclohexyl which is unsubstitutedor mono-, di- or tri-substituted by C₁ -C₄ alkyl; benzyl or a group ofthe formula (III); R₁₀ is C₂ -C₈ alkylene, C₄ -C₁₀ alkylene interruptedby 1, 2 or 3 oxygen atoms or by 1 or 2 ##STR87## groups where R₁₅ is asdefined above for R₁₄ or is C₁ -C₄ acyl or (C₁ -C₄ alkoxy)carbonyl;cyclohexylenedimethylene, methylenedicyclohexylene,isopropylidenedicyclohexylene, phenylenedimethylene orisopropylidenediphenylene; R₁₁ is C₂ -C₃ alkylene; G₄ is >N--(R₁₁-G₃)_(s) -- or >CH--O--, r and s which can be identical or different arezero or 1; R₁₂ is hydrogen or, when r is 1 and G₄ is >CH--O--, R₁₂ isalso methyl; R₈ is a direct bond or C₁ -C₈ alkylene; R₉ is C₂ -C₈alkylene, C₄ -C₈ alkylene interrupted by 1 or 2 oxygen atoms;cyclohexylenedimethylene or isopropylidenedicyclohexylene; and q is zeroor an integer from 1 to 3; when n is 3, A is aliphatic C₄ -C₈ triacyl,benzenetricarbonyl or a group of the formula (VIII) in which X₃ is asdefined above and E₂ is one of the groups of the formulae (IXa)-(IXc) inwhich G₅, G₆ and G₇ which can be identical or different are as definedabove for G₁, G₂ and G₃ ; R₁₆, R₁₇ and R₁₈ which can be identical ordifferent are C₂ -C₄ alkylene; t is zero or 1; R₁₉, R₂₀ and R₂₁ whichcan be identical or different are as defined above for R₁₄ ; G₈ is adirect bond or --CH₂ --; u and v which can be identical or different areintegers from 3 to 6; and R₂₂ is C₃ -C₆ alkanetriyl; when n is 4, A isaliphatic C₆ -C₈ tetraacyl,benzenetetracarbonyl or a group of theformula (Xa) in which X₃ is as defined above and E₃ is a group of theformulae (XIa)-(XIc) in which G₉ is as defined above for G₁, G₂ and G₃ ;R₂₃ and R₂₄ which can be identical or different are C₂ -C₄ alkylene; wis zero or 1; and R₂₅ is C₄ -C₆ alkanetetrayl.
 5. A compound of formula(I) according to claim 1, in which n is 1, 2, 3 or 4;when n is 1, A ismethyl, C₈ -C₁₈ alkyl or one of the groups of the formulae (IIa)-(IIc)in which X₁ and X₂ which can be identical or different are a group --OR₄or ##STR88## where R₄ is C₁ -C₈ alkyl or a group of the formula (III),R₅ and R₆ which can be identical or different are C₁ -C₈ alkyl,cyclohexyl, C₂ -C₃ alkyl substituted in the 2- or 3-position by methoxy,by ethoxy, by dimethylamino, by diethylamino or by 4-morpholinyl;tetrahydrofurfuryl or a group of the formula (III) or the group##STR89## is 4-morpholinyl; or R₅ is also hydrogen; R₂ is C₃ -C₁₇ alkyl,cyclohexyl, phenyl, 3,5-di-t-butyl-4-hydroxyphenyl or2-(3,5-di-t-butyl-4-hydroxyphenyl)-ethyl; p is zero; R₃ is C₄ -C₁₈alkyl, cyclohexyl, t-butylcyclohexyl or a group of the formula (III);when n is 2, A is one of the groups of the formulae (Va)--(Ve) in whichX₃ is as defined above for X₁ and X₂ or is a group of the formula (VI)E₁ is one of the groups of the formulae (VIIa)-(VIIb) in which G₁ and G₂which can be identical or different are --O-- or ##STR90## where R₁₄ ishydrogen, C₁ -C₈ alkyl, cyclohexyl or a group of the formula (III); R₁₀is C₂ -C₆ alkylene, C₆ -C₁₀ alkylene interrupted by 2 or 3 oxygen atoms;cyclohexylenedimethylene or methylenedicyclohexylene, the group (VIIb)is one of the groups ##STR91## where r and s which can be identical ordifferent are zero or 1; R₁₄ is as defined above;R₈ is C₂ -C₈ alkylene;R₉ is C₄ -C₈ alkylene or isopropylidenedicyclohexylene; and q is zero or1; when n is 3, A is a group of the formula (VIII) in which X₃ is asdefined above and E₂ is a group of the formula (IXa) or (IXb) in whichG₅ and G₆ which can be identical or different are as defined above forG₁ and G₂ ; R₁₆ and R₁₇ which can be identical or different are C₂ -C₃alkylene; t is zero; R₁₉, R₂₀ and R₂₁ are as defined above for R₁₄ ; G₈is a direct bond or --CH₂ --; u and v which can be identical ordifferent are integers from 3 to 5; when n is 4, A is a group of theformula (Xa) in which X₃ is as defined above and E₃ is a group of theformula (XIa) in which G₉ is as defined above for G₁ and G₂ ;R₂₃ and R₂₄which can be identical or different are C₂ -C₃ alkylene; and w is zeroor
 1. 6. A compound of formula (I) according to claim 1, in which R₁ ishydrogen or methyl;n is 1, 2, 3 or 4; when n is 1, A is methyl or one ofthe groups of the formulae (IIa)-(IIc) in which X₁ and X₂ which can beidentical or different are a group --OR₄ or ##STR92## where R₄ is C₁ -C₄alkyl, 2,2,6,6-tetramethyl-4-piperidyl or1,2,2,6,6-pentamethyl-4-piperidyl, R₅ and R₆ which can be identical ordifferent are C₁ -C₄ alkyl, cyclohexyl, tetrahydrofurfuryl,2,2,6,6-tetramethyl-4-piperidyl or 1,2,2,6,6-pentamethyl-4-piperidyl orthe group ##STR93## is 4-morpholinyl; or R₅ is also hydrogen; R₂ is C₅-C₁₇ alkyl; p is zero; R₃ is C₆ -C₁₈ alkyl, when n is 2, A is one of thegroups of the formulae (Va)-(Vd) in which X₃ is as defined above for X₁and X₂ or is a group of the formula (VI); E₁ is a group ##STR94## whereR₁₄ is hydrogen, methyl, 2,2,6,6-tetramethyl-4-piperidyl or1,2,2,6,6-pentamethyl-4-piperidyl; R₈ is C₄ -C₈ alkylene; and R₉ is C₄-C₆ alkylene, and, when n is 3, A is a group of the formula (VIII) inwhich X₃ is as defined above and E₂ is a group ##STR95## where R₁₄ is asdefined above, and, when n is 4, A is a group of the formula (Xa) inwhich X₃ is as defined above and E₃ is a group ##STR96## with R₁₄ beingas defined above.
 7. A compound of formula (I) according to claim 1, inwhich R₁ is hydrogen or methyl;n is 1, 2, 3 or 4; when n is 1, A ismethyl or a group of the formula (IIb) in which R₂ is C₅ -C₇ alkyl; whenn is 2, A is a group of the formula (Va) or (Vb), in which X₃ is a groupof the formula (VI) and E₁ is a group ##STR97## where R₁₄ is2,2,6,6-tetramethyl-4-piperidyl or 1,2,2,6,6-pentamethyl-4-piperidyl;when n is 3, A is a group of the formula (VIH) in which X₃ is as definedabove and E₂ is a group ##STR98## and, when n is 4, A is a group of theformula (Xa) in which X₃ is as defined above and E₃ is a group ##STR99##